StarSwitcher TnA (and others) repair thread

Well, I couldn't help myself, and opened up everything today. I'll post pics of everything later. A bit p i s s e d, the majority of the trains don't work, and have zero cash to ship out anything. Does anybody have any tutorials on how to fix the Talk N Action engines? Those have weird problems. Gordon will (barely) work, no sound. Thomas talks and sings, but his wheels barely move (solved, the white axel is loose). Henry does barely anything and doesn't talk. James works great with a little help of a back engine. Diesel 10 frankly enough worked the best, and apparently had the worst corrosion of battery I have seen in my life.

That was the worst of it, yet still worked. Any help on any DiY repair with any Tomy and the TNA engines would be appreciated!

Found a pic I posted in one of the older threads- that's the D10 in your hands when I unwrapped it.